CN113098425A - Impedance matching network, adaptive impedance matching device and method thereof - Google Patents
Impedance matching network, adaptive impedance matching device and method thereof Download PDFInfo
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Abstract
The invention discloses an impedance matching network, a self-adaptive impedance matching device and a self-adaptive impedance matching method, wherein the impedance matching network consists of a variable capacitor and a variable inductor, wherein the variable capacitor consists of at least two capacitors connected in parallel, the value of the capacitor is gradually decreased, and the value of the maximum capacitor is determined by the variation range of the variable capacitor; the variable inductor is composed of at least two inductors connected in series, the value of the inductor is gradually decreased, and the maximum value of the inductor is determined by the variable inductor variation range. The self-adaptive impedance matching device comprises a sampling module, the impedance matching network and a controller, wherein the controller receives a sampling signal and then executes the calculation of load impedance, so that the characteristic parameters of the impedance matching network corresponding to the impedance matching state are determined, and the impedance matching network is adjusted according to the characteristic parameters, so that the impedance matching is realized. The impedance matching network and the self-adaptive impedance matching device have the advantages of wide matching range, high matching precision flexibility, high reliability, low cost, quick response, simple implementation mode and the like.
Description
Technical Field
The invention relates to the field of medical beauty equipment, in particular to an impedance matching network, a self-adaptive impedance matching device and a self-adaptive impedance matching method.
Background
Many medical and cosmetic treatments involve the use of high frequency, high power energy to treat a patient, and in non-invasive cancer treatments, skin care, weight loss, muscle augmentation, etc., energy is injected into the patient in the form of microwaves, radio frequencies, ultrasound, etc. to achieve a therapeutic effect.
When energy is injected into a human body through a transmission line, the problem that the transmission line is matched with the load impedance of the human body is involved, and the voltage reflection coefficient gamma of a lossless transmission line is defined as:
wherein Z is0A transmission line characteristic impedance, typically 50 ohms; zloadThe load impedance, in relation to the material properties, the geometry and the like of the load,
is normalized impedance;
and
the voltage phasors respectively represent the incident wave and the reflected wave and are complex numbers; the reflected power of the transmission line is:
Preflection＝Pincident×|Γ|2 (2)
wherein, Preflection，PincidentRepresenting reflected and incident power, respectively; it can be seen that the smaller the Γ, the smaller the reflected energy, when Z isload＝Z0Impedance matching is achieved, and the reflected energy is 0; to illustrate, in the case of surgical operation, the treatment site impedance Zload500-050 Ω, the absolute value of the voltage reflection coefficient | Γ | > is 0.75, and the ratio of the reflection energy to the incident energy is | Γ | >2At 0.56, more than half of the energy is reflected.
It follows that impedance matching is extremely important, and impedance mismatching has the following disadvantages: firstly, reflected power is absorbed by an energy source to damage the energy source; due to the large reflected power, the effective power for treatment is reduced, and the treatment effect is weakened; thirdly, in order to improve the effective power, the incident power needs to be correspondingly increased, but the voltage and the current amplitude of the whole system are increased, so that potential safety hazards are generated; meanwhile, high current generates a large amount of heat in the system, and the energy utilization efficiency is poor; moreover, if a plurality of devices are used simultaneously, the power amplitude may exceed the allowable range of the commercial power; different patients and different body parts of the same patient have changed impedance, and the change of the body position of the patient during treatment also causes impedance transformation, if the instant impedance matching is not carried out, the treatment effect will be different from person to person and from part to part, and the patient feels unstable, if some parts obtain high energy, the patient feels burning pain, and other parts obtain low energy, and the treatment effect is not good.
The commonly used impedance matching method is that an impedance matching network is added between an energy source and a load, the input end of the impedance matching network is connected with the output end of the energy source through a transmission line, and the output end of the impedance matching network is connected with the load; the impedance matching network generally adopts two passive devices, namely a capacitor and an inductor, and an energy transition area is established between a sensing line and a load by utilizing the energy storage characteristics of the passive devices; the impedance matching network and the load are integrated as a whole from the output end of the transmission line, and the impedance of the impedance matching network and the impedance of the transmission line are the same, so that energy reflection is reduced; and because the capacitor and the inductor are passive devices, the stored energy is input to the load end, and the load obtains the maximum effective power.
Currently commonly used impedance matching networks include: pi-type, Γ -type, T-type, and the like; for a load with a specific impedance value, the impedance matching can be realized only by adjusting the values of the capacitance and the inductance on the impedance matching networks.
However, in some cases, the impedance value of the load may change frequently, for example, when performing a medical operation, a slight adjustment of the body posture of the patient may cause a large change in the impedance at the load end, so the control system needs to monitor the change in time, and adjust the corresponding capacitance and inductance values to match the impedance again.
At present, a commonly used method for implementing an adjustable capacitor and an adjustable inductor includes: 1) the mechanical method is that a motor is used for driving a variable capacitor, the method has slow response speed and relatively high failure rate after long-time use; 2) the varactor is used for adjusting the capacitance by adjusting reverse bias voltage, but the value of the varactor is in a pF magnitude, the adjustable range is very small, and the varactor is not suitable for loads with higher power; 3) the adjustable capacitor can be realized by two groups of equidirectional windings sleeved on the same magnetic ring, direct current is conducted on the winding 1, and the magnetic saturation of the magnetic ring can be finely adjusted by controlling the intensity of the direct current, so that the inductance value of the winding 2 can be indirectly changed.
Therefore, the prior art has yet to be developed.
Disclosure of Invention
Aiming at the problems of slow response speed, small adjusting range and difficult application to loads with larger functions of the existing impedance matching device, the embodiment of the invention provides an impedance matching network, a self-adaptive impedance matching device for an energy source medical cosmetic instrument and a method for calculating load impedance and realizing self-adaptive impedance matching.
The invention provides the following technical scheme:
in a first aspect, the present invention provides an impedance matching network applied to an adaptive impedance matching apparatus, which mainly comprises a variable capacitor and a variable inductor; the impedance matching network realizes the adjustable capacitance and the adjustable inductance by combining the capacitance and the inductance with a plurality of fixed values, and has the advantages of wide matching range, flexible control of matching precision according to actual conditions, high reliability, low cost, quick response, simple realization mode and the like.
The variable capacitor is composed of at least 2 capacitors connected in parallel, the value of the capacitor is gradually decreased, and the maximum value of the capacitor is determined by the variable capacitor change range;
the variable inductor is composed of at least 2 inductors connected in series, the value of the inductor is gradually decreased, and the maximum value of the inductor is determined by the variable inductor variation range.
The number of capacitors and inductors depends, among other things, on the accuracy requirements. The number of the adjustable capacitors or the adjustable inductors can be correspondingly selected according to the requirement on the adjustment precision of the adjustable capacitors or the adjustable inductors.
In the most preferred embodiment, the values of the capacitances constituting the variable capacitance are gradually decreased by multiples of 1/2; and/or the values of all the inductors forming the variable inductor are gradually decreased according to the multiples of 1/2.
In this embodiment, since the variable capacitor is composed of n capacitors with fixed values, the values of the fixed capacitors can be determined according to the following formula:
the capacitance range to be adjusted is [ C ]low，Chigh]Then the change value of the capacitance is dC ═ Chigh-Clow(ii) a The adjustment is carried out by n capacitors, and the value of the first fixed capacitor is dC/2, and the value of the second fixed capacitor is dC/22The rest are analogized in turn, and the value of the nth fixed capacitor is dC/2n(ii) a The n capacitance-adjustable capacitance ranges [0, dC ]]Adding a capacitor C connected all the timelowThe adjustable capacitance range becomes [ C ]low，Chigh]With an adjustment accuracy of
The number n of the capacitors depends on the precision requirement, and n is more than or equal to 2. And the value of n can be correspondingly taken according to the requirement on the adjustment precision of the adjustable capacitor bank.
For an adjustable capacitor group consisting of n capacitors according to the value mode, the maximum absolute error is
In fact, this combination method simulates the way of counting binary decimal numbers, each capacitor corresponds to one bit of the binary decimal number, and the capacitor is accessed to represent that the corresponding binary decimal digit is 1, otherwise, the capacitor is 0.
The adjustable inductor is realized by a plurality of fixed value inductors, the principle of the adjustable inductor is similar to that of the adjustable capacitor, and the adjustable inductor is not described again.
In practical engineering application, because of the non-perfect passive device of the capacitance and the inductance, the real part resistance of the passive device is also considered when impedance matching calculation is carried out; meanwhile, the capacitance inductance value used in the engineering is not taken according to the relation of 1/2 times, and can be properly deviated from 1/2 times when a fixed capacitance inductance value is selected; in both cases, 1/2 times of perfect capacitance resistance can be assumed in advance, and after a preliminary result is obtained, the fine tuning is finally carried out through an algorithm. Therefore, in other embodiments, the value of each capacitor can be gradually decreased by a multiple of 0.4-0.6; the value of each inductor can be gradually decreased according to a multiple of 0.4-0.6.
In order to control the working state of the capacitor or the inductor, an electromagnetic switch, such as a relay, is connected in parallel to both ends of the capacitor or the inductor, and the electromagnetic switch controls whether the corresponding capacitor or inductor is connected to the impedance matching network, so that the characteristic parameters of the impedance matching network are changed, and the impedance matching is realized.
In order to prevent high voltage current from being generated at the switching instant of the relay, the relay needs to be selected with reference to the time constant of the circuit, and the response time of the relay is required to be at least 10 times of the time constant, so that for the charged capacitor inductor, the short circuit is a slow process, so that high voltage cannot be generated at the two ends of the inductor, and high current cannot be generated at the two ends of the capacitor. For a human body as a load impedance and a 50 ohm transmission line, the time constant of the corresponding impedance matching network is picoseconds (10)-12s) magnitude, while the response time of a normal relay (non-rf relay) is microseconds (10)-6s) magnitude, completely meeting the safety requirement. Therefore, the impedance matching network has low requirement on the installed relay, and the common relay can meet the use requirement, is easy to obtain and has lower cost.
In a second aspect, the present invention also provides an adaptive impedance matching device for an energy source medical cosmetic apparatus, comprising:
the sampling module is used for acquiring an electric signal on a transmission line between the energy source and the impedance matching network; the signal output end of the sampling module is connected with the controller;
the impedance matching network is connected between the energy source and the load, the output end of the energy source is connected with the input end of the impedance matching network, and the output end of the impedance matching network is connected with the load;
and the input end of the controller is connected with the sampling module, and the output end of the controller is connected with the impedance matching network. The controller receives the sampling signal and then executes the calculation of the load impedance, thereby determining the characteristic parameters of the corresponding impedance matching network in the impedance matching state, and adjusting the impedance matching network according to the characteristic parameters, so that the impedance matching network and the load as a whole realize the impedance matching with the transmission line.
Preferably, in the adaptive impedance matching apparatus, the collected electrical signal is a voltage amplitude of an incident wave and a reflected wave on a transmission line connecting the energy source and the impedance matching network.
Each capacitor or inductor is connected in series or in parallel with an electromagnetic switch used for controlling whether the capacitor or inductor is connected into the impedance matching network or not; the electromagnetic switch controls whether the corresponding capacitor or inductor is connected to the impedance matching network, so that the characteristic parameters of the impedance matching network are changed, and the impedance matching is realized.
Preferably, in the adaptive impedance matching apparatus, the controller is connected to the electromagnetic switch in a control manner, and the on-off state of the electromagnetic switch is controlled by the controller.
In a third aspect, to overcome the disadvantages of the conventional impedance measuring method in the background art, the present invention further provides a method for calculating load impedance, which includes the following steps:
s1, the sampling module collects the electric signal on the transmission line between the energy source and the impedance matching network and transmits the electric signal to the controller;
s2, after the controller receives each group of electric signals sent by the sampling module, a closed curve which is related to the load impedance and is positioned on the complex plane is calculated by combining the characteristic parameters of the impedance matching network in the state;
preferably, the electrical signal collected by the sampling module is the voltage amplitude of the incident wave and the voltage amplitude of the reflected wave, and the absolute value of the voltage reflection coefficient Γ can be correspondingly solved as follows:
in formula (4), Γ is a complex number, and Γ ═ Γ | ejθθ ∈ [0, 2 π); that is, on the Γ complex plane, from the measured voltage amplitudes of the incident and reflected waves, it can be inferred that the true reflection coefficient Γ necessarily falls on a circle with a radius of | Γ |, or that true Γ is a certain point on the circle; from equation (1), the normalized impedance can be solved as follows:
wherein
Is the normalized impedance of the impedance matching network and the load as a whole; due to | Γ | ejθA closed curve is formed as a circle, and a closed curve is also formed on a complex number plane expressed by the formula (5), which is true
Is a point on the closed curve; load impedance ZloadCan be prepared from
And configuration calculation of impedance matching network, for the same reason, ZloadThe possible value-taking point of (A) is also a closed curve on the complex number plane, true ZloadMay be any point on the closed curve.
S3, adjusting characteristic parameters of the impedance matching network, and repeating the steps S1 and S2 to obtain at least two intersected closed curves in total; one of the closed curve intersections is the true load impedance.
In particular, the control of electromagnetic switches (e.g. relays) is regulated by a controllerThe value of the adjustable capacitance inductance on the whole impedance matching network is measured again to obtain another value related to ZloadA closed curve of (d); the two closed curves necessarily have two intersections, one of which is the true load impedance ZloadAnd the other intersection point is an interference term and needs to be eliminated.
To find the true load impedance, one embodiment is: the value of the adjustable capacitance inductance can be adjusted again to obtain a third band about ZloadThe common intersection point of the three closed curves is the real load impedance.
Determined by physical relationship, the above three items relate to ZloadThe closed curves of (a) necessarily have a common intersection point; if there is no common intersection point in the actual measurement, it is inevitable that an error is introduced in the measurement; the problem that the common intersection point is changed into three very close pairwise intersection points only due to small measurement errors can be solved through an algorithm, and if the measurement errors are large, the common intersection point cannot be determined and a measurement system needs to be corrected.
In another embodiment, based on two intersection points of two closed curves, the switching state of the electromagnetic switch set in the impedance matching state can be calculated respectively by the two intersection points, the two states are implemented respectively by the controller, for each state, the corresponding voltage reflection coefficient is measured, and the smaller one is the impedance matching state.
In a fourth aspect, the present invention further provides a method for implementing adaptive impedance matching, where the method includes: after the load impedance is calculated according to the method, the following steps are carried out:
s4, calculating characteristic parameters of an impedance matching network required for achieving impedance matching according to the real load impedance, and calculating the on-off state of an electromagnetic switch group in the impedance matching network according to the characteristic parameters;
and S5, the controller regulates each electromagnetic switch to a corresponding on-off state, so that the impedance network is adjusted to an impedance matching state.
Preferably, the step S4 is specifically: and calculating a target adjustable capacitance inductance value required for achieving impedance matching according to the real load impedance, converting the target adjustable capacitance inductance value according to a binary expression to obtain a final value, wherein the figure after the decimal point of the final value is the switching state of the electromagnetic switch of the corresponding capacitor. The steps described above except for S1 are all implemented in the controller.
The technical scheme provided by the invention has the following beneficial effects:
1. the impedance matching network and the self-adaptive impedance matching device simulate a binary fractional counting mode, n (n is more than or equal to 2) capacitors are used for realizing adjustable capacitance in a combined mode, and the relative error is 1/2n+1(ii) a Correspondingly, m (m is more than or equal to 2) inductors are used for realizing adjustable inductance in a combined mode, and the relative error is 1/2m+1. In the invention, the inductance value of the adjustable capacitor is determined by combining the algorithm with the sampling data; the sampling module and the controller monitor the change of the load impedance in real time, and the impedance matching network is adjusted through the monitoring result to realize the real-time self-adaptive impedance matching. A common 8-bit singlechip is combined with a 100kHz ADC, the corresponding adaptive impedance matching time is in the millisecond order, and if a microprocessor with higher clock frequency is combined with a high-frequency ADC, the adaptive impedance matching time can reach the microsecond order.
Therefore, the impedance matching network and the adaptive impedance matching device have the advantages of wide matching range, high matching precision and flexibility, high reliability, low cost, quick response, simple implementation mode and the like; the self-adaptive impedance matching device is more suitable for energy source medical beauty treatment instruments, and has good application prospect in the field of beauty treatment instruments.
2. The method for calculating the load impedance and realizing the impedance matching can calculate the load impedance only by measuring the voltage amplitude of the incident wave and the reflected wave; it has the following advantages:
the requirements on sampling speed and time precision are greatly reduced, and time control equipment such as a crystal oscillator is not needed; secondly, different from the fast Fourier transform method, a large number of data sequences are required, and the method only needs to adopt a small number of data points, so that the memory space of the controller can be saved; and thirdly, because accurate time sampling is not needed, the Nyquist sampling theorem is not needed to be satisfied, the requirement on the working frequency of the sampling ADC is low, and the requirement on the calculation speed of the controller is low. The invention has the significance of realizing the instant self-adaptive impedance matching of medical and aesthetic instruments under radio frequency and microwave frequency bands by using lower hardware cost.
Drawings
Fig. 1 is an adaptive impedance matching device for an energy source medical cosmetic apparatus according to the present invention;
FIG. 2 is a schematic diagram of an F-type impedance matching network in one embodiment; the gamma-type impedance matching network consists of 6 capacitors and 6 inductors, wherein 5 capacitors and 5 inductors participate in capacitance and inductance adjustment;
FIG. 3 is a particular embodiment of a sampling module;
FIG. 4 is a diagram of one embodiment of the method of calculating load impedance of the present invention, which is only for assisting understanding of the calculation method, and does not need to be plotted in practical engineering application, and the impedance solution is automatically realized by an algorithm in a calculation program;
FIG. 5 is a flow chart of a method of calculating load impedance of the present invention;
fig. 6 is a flow chart of a method for implementing adaptive impedance matching according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Some embodiments of the impedance matching network applied to the adaptive impedance matching device, the adaptive impedance matching device applied to the energy source medical cosmetic apparatus, the corresponding calculation method of the load impedance, and the method for implementing the adaptive impedance matching, which are proposed in the summary of the invention, are explained below.
Example 1
The Γ -type impedance matching network shown in fig. 2 comprises 6 capacitors and 6 inductors, wherein the variable capacitor comprises 5 capacitors C1-C5 connected in series, and the variable inductor comprises 5 inductors L1-L5 connected in parallel. C1-C5 and L1-L5 are respectively connected with corresponding relays, and the relays are controlled by the controller, so that the adjustable capacitance and inductance are realized. In this embodiment, the capacitance values of the adjacent capacitors are successively reduced to 1/2 of the original capacitance value; the inductance value of the adjacent inductors is successively reduced to 1/2 of the original inductance value.
Therefore, the relative errors of the variable capacitance and the inductance are 1/261.56%, in other embodiments, the number of capacitors and inductors may be increased if the adjustment accuracy is to be improved.
The access state of the relay set corresponding to the capacitor is determined by the following method: assuming that the adjustable capacitance value required for impedance matching is calculated to be CtDefinition of r ═ Ct-Clow) and/dC, then r is a decimal number with a numeric range of [0, 1]And calculating the binary expression of r, wherein the front 5 bits after the decimal point are the switching state of the relay of the corresponding capacitor. For example, when the binary expression corresponding to r is 0.23 is 0.00111, the relay corresponding to the 1 st and 2 nd bit capacitors is turned off, and the relay corresponding to the 3 rd, 4 th and 5 th bit capacitors is turned on.
In the embodiment shown in fig. 2, since the connection modes of the inductor and the capacitor are different, when the relay corresponding to the inductor is disconnected, the inductor is connected to the impedance matching circuit; accordingly, if r ═ Lt-Llow) When the binary expression of/dL is 0.00111, the relays corresponding to the 1 st and 2 nd inductors are switched on, and the relays corresponding to the 3 rd, 4 th and 5 th inductors are switched off.
It is worth noting that, because the actual capacitance and inductance have real part resistance, the resistance value of the relay in the on state is not completely 0; for each capacitance and inductance, the impedance of the capacitance and inductance at the working frequency when the relay is opened and closed can be measured in advance by a Vector Network Analyzer (Vector Network Analyzer), and the impedance values are written into a control program as parameters.
Fig. 2 shows an embodiment with a relative error of 1.56% for an impedance matching network of the Γ type, but the method can be applied to other types of impedance matching networks, while the corresponding accuracy can be adjusted according to specific engineering requirements.
As shown in fig. 1, the present embodiment also provides an adaptive impedance matching apparatus for an energy source medical cosmetic device, which includes:
the sampling module 1 is used for acquiring an electric signal on a transmission line between an energy source and an impedance matching network; the signal output end of the sampling module is connected with the controller;
the impedance matching network 2 is connected between the energy source 4 and the load 5, the output end of the energy source is connected with the input end of the impedance matching network, and the output end of the impedance matching network is connected with the load;
the controller 3 is used for receiving the sampling signal and then executing the calculation of the load impedance so as to determine the characteristic parameters of the corresponding impedance matching network in the impedance matching state, and adjusting the impedance matching network according to the characteristic parameters so that the impedance matching network and the load as a whole realize impedance matching with the transmission line; the input end of the controller 3 is connected with the sampling module 1, and the output end of the controller is connected with the impedance matching network.
The controller 3 is in control connection with the relay, and the on-off state of the relay is controlled by the controller 3, so that whether a capacitor or an inductor corresponding to the relay is connected to the impedance matching network 2 or not is controlled, the characteristic parameters of the impedance matching network are changed, and impedance matching is achieved.
Example 2
Based on the impedance matching network and the adaptive impedance matching device applied in embodiment 1, this embodiment provides an impedance measuring method.
One implementation of the sampling module is shown in fig. 3. It uses twoThe directional coupler measures the voltage amplitude of the incident wave and the reflected wave, which is a widely applied and cheap transmission line voltage measuring method; wherein, V+、V-With voltages at both ends corresponding to the amplitude of the incident and reflected waves, respectively
The measurement can be performed using a common ADC. Since the diode is turned on with a forward voltage drop, the voltage values collected by the ADC need to be corrected to obtain the actual voltage amplitudes of the incident and reflected waves.
In combination with the impedance matching network shown in fig. 2 and the sampling module shown in fig. 3, the present embodiment provides an optimized impedance measurement method, which specifically includes the following steps:
s1, the sampling module 1 collects the electrical signal (in this embodiment, the amplitude of the incident and reflected wave voltage is measured) on the transmission line between the energy source and the impedance matching network, and transmits the electrical signal to the controller 3; after receiving each group of electric signals sent by the sampling module, the controller 3 calculates a closed curve located on the complex plane and related to the load impedance by combining the characteristic parameters of the impedance matching network in the state.
Specifically, the controller 3 measures and measures the voltage amplitudes of the incident wave and the reflected wave, and obtains a reflection coefficient absolute value | Γ | by the formula (4); accordingly, the impedance matching network and the load as a whole have normalized impedances
It can be calculated from equation (5), which corresponds to a closed curve on a complex number plane.
S2, based on the gamma-type impedance matching network, setting the normalized admittance value corresponding to the adjustable capacitor as
The adjustable inductor has a normalized impedance value of
Corresponding load normalized impedance
Can be calculated from the following formula:
wherein
Corresponding to a closed curve on the complex plane.
S31, adjusting the value of the adjustable capacitance and inductance to obtain a new value
Repeating the steps 1-2 to obtain three intersected closed curves in total;
and judging by an algorithm, and if the three closed curves have a common intersection point in a specified precision range, determining the intersection point as a normalized impedance value of the load, namely the real load impedance.
If the common intersection point can not be found within the specified precision range, repeating the steps S1-4 to carry out measurement, and if the common intersection point can not be found in multiple times of measurement, indicating that the system has a large measurement error, needing to give an alarm and correcting the system again.
Fig. 4 is a diagram of the intersection points of the three closed curves in the step S31, and it should be noted that the method for solving impedance by finding the intersection points of the curves shown in fig. 4 is only for understanding this embodiment, and it is not necessary to draw the diagram in actual calculation, and the solution of the intersection points of the curves is implemented by an algorithm inside a calculation program; therefore, the whole solving process is completely automatic, the calculating speed is high, and the instant self-adaptive impedance matching can be realized.
In step S4, since the actual capacitance and the actual relay both have real resistors and the capacitance and inductance values are not exactly valued in the form of 1/2 multiples, the on-off state of the relay can be calculated according to the ideal capacitance and inductance values, and then fine tuning is performed on the basis; or directly calculating violence, and finding out the switch state of the relay group corresponding to the minimum reflection coefficient in a mode of traversing all the switch state combinations of the relays.
In another embodiment, a slightly different impedance measurement method is provided, which is based on the above method and is designed as follows:
S1-S2, the steps are the same as the above embodiment;
s32, adjusting the value of the primary adjustable capacitance and inductance to obtain a new value
Repeating the steps 1-2 to obtain two intersected closed curves in total;
the two closed curves have two intersections, both of which are likely to be actual load impedances. The switching state of the relay set in the impedance matching state can be calculated by the two intersection points respectively, the two states are implemented by the controller respectively, the voltage reflection coefficient corresponding to each state is measured, and the smaller state is the impedance matching state.
The embodiment also provides a method for realizing adaptive impedance matching, which comprises the following steps:
firstly, the above-mentioned S1-S3 is performed, and after obtaining the real load impedance, the following steps are performed:
s4, calculating the adjustable capacitance and the adjustable inductance needed for reaching impedance matching by the real load impedance, and calculating the two values by the binary decimal method, thereby obtaining the on-off state of each relay;
and S5, after the controller regulates and controls the relays to be in the corresponding on-off states, the impedance network is adjusted to be in an impedance matching state.
The above-described embodiments of the apparatus and method are merely exemplary, which are only specific embodiments of the present invention, and are intended to illustrate the technical solutions of the present invention, not to limit the present invention. It should be understood that the technical solutions and concepts of the present invention may be equally replaced or changed by those skilled in the art, and all such changes or substitutions should fall within the protection scope of the appended claims.
Claims (10)
1. An impedance matching network applied to a self-adaptive impedance matching device is characterized by mainly comprising a variable capacitor and a variable inductor;
the variable capacitor is composed of at least 2 capacitors connected in parallel, the value of the capacitor is gradually decreased, and the maximum value of the capacitor is determined by the variable capacitor change range;
the variable inductor is composed of at least 2 inductors connected in series, the value of the inductor is gradually decreased, and the maximum value of the inductor is determined by the variable inductor variation range;
each capacitor or inductor is connected in series or in parallel with an electromagnetic switch used for controlling whether the capacitor or inductor is connected into the impedance matching network or not.
2. The impedance matching network of claim 1, wherein values of the capacitances constituting the variable capacitance are gradually decreased by multiples of 0.4 to 0.6.
3. The impedance matching network of claim 1, wherein values of the inductances that form the variable inductance are gradually decreased by multiples of 0.4 to 0.6.
4. The impedance matching network of claim 2 or 3, wherein values of the capacitances constituting the variable capacitance are successively decreased by multiples of 1/2; the values of all the inductors forming the variable inductor are gradually decreased according to the multiples of 1/2.
5. An adaptive impedance matching apparatus for an energy source cosmeceutical device, comprising:
the sampling module (1) is used for acquiring an electric signal on a transmission line between an energy source and the impedance matching network; the signal output end of the sampling module is connected with the controller;
the impedance matching network (2) of claim 1, connected between an energy source (4) and a load (5), the energy source output being connected to the impedance matching network input, the impedance matching network output being connected to the load;
the controller (3) is used for receiving the sampling signal and then executing the calculation of the load impedance, so as to determine the characteristic parameters of the corresponding impedance matching network in the impedance matching state, and adjust the impedance matching network according to the characteristic parameters, so that the impedance matching network and the load as a whole realize impedance matching with the transmission line; the input end of the controller (3) is connected with the sampling module (1), and the output end of the controller is connected with the impedance matching network.
6. The adaptive impedance matching device according to claim 5, wherein the collected electrical signals are voltage amplitudes of incident and reflected waves on a transmission line connecting the energy source (4) and the impedance matching network (2).
7. The adaptive impedance matching device according to claim 6, wherein each capacitor or inductor is connected in series or in parallel with an electromagnetic switch for controlling whether the capacitor or inductor is connected to the impedance matching network; the electromagnetic switch controls whether the corresponding capacitor or inductor is connected to the impedance matching network (2) or not, so that the characteristic parameters of the impedance matching network are changed, and impedance matching is realized.
8. The adaptive impedance matching device according to claim 5, wherein the controller (3) is in control connection with the electromagnetic switch, and the on-off state of the electromagnetic switch is controlled by the controller (3).
9. A method of calculating load impedance, comprising the steps of:
s1, the sampling module (1) collects an electric signal on a transmission line between the energy source and the impedance matching network and transmits the electric signal to the controller (3);
s2, after receiving each group of electric signals sent by the sampling module, the controller (3) calculates a closed curve which is positioned on a complex plane and is related to the load impedance by combining the characteristic parameters of the impedance matching network in the state;
s3, adjusting characteristic parameters of the impedance matching network through the controller, and repeating the steps S1 and S2 to obtain at least two intersected closed curves in total; one of the closed curve intersections is the true load impedance.
10. A method for realizing adaptive impedance matching is characterized in that the method comprises the following steps: after calculating the load impedance according to the method of claim 9, performing the steps of:
s4, calculating characteristic parameters of an impedance matching network required for achieving impedance matching according to the real load impedance, and calculating the on-off state of an electromagnetic switch group in the impedance matching network according to the characteristic parameters;
and S5, after the controller regulates and controls each electromagnetic switch to be in a corresponding on-off state, the impedance network is adjusted to be in an impedance matching state.
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